Why would a superstar like Whitney Houston turn to drugs and send her seemingly charmed life spiraling toward destruction? In a new documentary, “Whitney,” opening in theaters on July 6, filmmaker Kevin Macdonald attempts to answer that question, but ends up raising even more.

Anyone who is old enough to remember the sensation of shock and sadness caused by the deaths of music icons Jimi Hendrix, Janis Joplin and Jim Morrison in the early 1970s is well-aware of the history of substance abuse and its connection to rock and roll. Still, that didn’t make the passing of Michael Jackson, Amy Winehouse or Prince, years later, any less difficult to bear.